In a conventional process of producing complementary SiGe bipolar transistors, collector and base zones of the two conductivity types are formed in adjacent areas on a support wafer. An emitter interface oxide layer is then grown simultaneously for both transistors, and the emitters are patterned thereon. The presence of an interfacial oxide reduces the base current and increases the transistor gain. The interface oxide, however, creates a higher barrier for hole than for electron tunneling so that the NPN gain increases much more than the PNP gain. An increase in gain reduces the transistor breakdown voltage. A thickness of the interface oxide layer sufficient to improve the PNP gain causes the NPN breakdown voltage to drop below acceptable values. This can be corrected by increasing the NPN base dose, but at the cost of reducing transistor speed. An increase in base dose not only increases the Gummel number, it also reduces electron mobility, increases emitter-base capacitance, and slightly increases the base width. The net result of an increased base dose is a drop in the transient frequency (fT) by about 4 GHz.